Conventionally, an electromagnetic valve is used, for example, as a decompression valve shown in FIGS. 4A and 4B. The decompression valve discharges and decompresses high-pressure fuel stored in a common rail (e.g., JP 2009-103050 A). An electromagnetic valve 100 includes a housing 101, a rod 102 slidable in its axial direction in the housing 101, an armature 104 fixed to the rod 102 and magnetized upon energization of a solenoid coil 103 to be magnetically attracted to one side in the axial direction, and a stopper 105 that limits the motion of the armature 104 toward the one side in the axial direction by contacting at least one of the armature 104 and the rod 102. A valve body 108 is provided at a tip of the rod 102 to open or close a valve hole 109 provided in the housing 101 in accordance with the motion of the rod 102.
The armature 104 is fixed to the rod 102, for example, by press-fitting the rod 102 into a rod hole 110 provided in the armature 104. In the electromagnetic valve 100 shown in FIGS. 4A and 4B, when the armature 104 moves to the one side in the axial direction, an end of the rod 102 on the one side in the axial direction contacts the stopper 105, so that the motion of the armature 104 is limited.
When the armature 104 moves to the one side in the axial direction to contact the stopper 105, an end surface of the armature 104 on the one side in the axial direction is subjected to a fuel pressure. Accordingly, the armature 104 may be deformed so that the rod hole 110 expands as shown in FIG. 4B. As a result, the armature 104 may be damaged, and the armature 104 may be unfixed from the rod 102, so that the rod 102 can be pulled out of the rod hole 110.
Moreover, when the armature 104 is deformed, a gap between the armature 104 and a stator core 111, magnetized by the solenoid coil 103 to attract the armature 104, is changed, and the attraction force between the armature 104 and the stator core 111 may thereby reduce. As a result, responsiveness of the electromagnetic valve 100 may reduce.
It is an objective of the present disclosure to limit deformation of an armature and a rod fixed to the armature in an electromagnetic valve when the armature moves to one side in an axial direction of the rod, and when the armature or the rod contacts a stopper.